Microfluidic devices have potential applications in biotechnology, microchemical systems, fine chemicals industry, pharmaceuticals, fuel cells, microelectromechanical systems (MEMS), and the like. Recent research has focused on devices formed by the connection of a series of individual microfluidic systems to form an integrated or modular microchemical system, optionally with sensors and other means for online analysis, similar to a miniaturized chemical plant. For example, it would be advantageous to have the ability to perform a multi-step chemical synthesis using a series of microreactors and micro-phase-separators connected in series to form a chemical product. Systems such as these would reduce the time and cost of synthesizing various commercial products.
Insufficient attempts have been made to address the issues of connecting the individual devices in order to create a such “miniaturized chemical plants.” This may be attributed to the lack of micro-versions of pumping devices used in conventional chemical industry. For example, current syringe pumps provide essentially the same fluid flow rate through all the connective devices, which often results in a pressure decay along the pressure profile the system. This limitation does not allow the connection of the series of devices, each having a different flow rate. Many current systems comprise a single pump attached at the beginning of a series of devices, such that the flow rate provided by the pump decays as it travels through each device. Additionally, the microfabricated valves and pumps produced using multilayered soft lithography often employ elastomers such as silicones that are not compatible with harsh chemicals. Moreover, these materials can only handle very small flow rates and volumes, and the flows often show fluctuations.
Accordingly, improved devices and methods are needed.